Conventional production of semiconductor devices has employed lithographic microfabrication using a photoresist composition. In the microfabrication, the photoresist composition is formed into a thin film on a silicon wafer; active light such as ultraviolet light is applied to the photoresist through a mask pattern with a pattern for a semiconductor device; the photoresist is developed; and the silicon wafer is etched using the obtained resist pattern as a protective film. In recent years, a semiconductor device has been further integrated and the wavelength of the active light to be used has been shortened from an i-line (wavelength 365 nm) and a KrF excimer laser (wavelength 248 nm) to an ArF excimer laser (wavelength 193 nm). Such a change raises serious issues of the influence of irregular reflections of active light from a substrate or standing waves. To address the issues, an anti-reflective coating (bottom anti-reflective coating) between the photoresist and the substrate has been widely studied.
Increasingly finer patterns cause pattern collapse in a lithography process. Such an issue arises in processes of development and rinsing a developer after exposure of a resist.
The pattern collapse is supposed to be caused by surface tension of a developer or a rinse solution during drying or a force applied between patterns by the force associated with liquid flow, namely, Laplace force. Furthermore, the Laplace force is supposed to cause pattern collapse also when the developer or the rinse solution is spun off to the outside by a centrifugal force.
In order to solve such a problem, a pattern forming method is disclosed. The method includes forming a resist film on a substrate, selectively irradiating the resist film with an energy beam in order to form a latent image in the resist film, supplying a developer (alkali developer) onto the resist film in order to form a resist pattern from the resist film having the latent image, supplying a rinse solution onto the substrate in order to replace the developer on the substrate with the rinse solution, supplying a coating film material onto the substrate in order to replace at least a part of the rinse solution on the substrate with the coating film material containing a solvent and a solute different from that in the resist film, volatilizing the solvent in the coating film material in order to form a coating film covering the resist film on the substrate, removing at least a part of a surface on the coating film in order to expose at least a part of a top surface of the resist pattern and to form a mask pattern including the coating film, and processing the substrate using the mask pattern (see Patent Document 1).